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# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
import logging
import dbus
from dbus.gobject_service import ExportedGObject
from dbus.service import method, signal
import port.json as json
from sugar.presence import presenceservice
import char
import ground
import sound
from document import Document
logger = logging.getLogger('cartoon-builder')
SERVICE = 'org.sugarlabs.CartoonBuilder'
IFACE = SERVICE
PATH = '/org/sugarlabs/CartoonBuilder'
class Slot:
def __init__(self, sender=None, raw=None):
if sender:
data = json.loads(raw)
self.seqno = data['seqno']
self.oid = data['oid']
self.sender = sender
else:
self.seqno = -1
self.oid = None
self.sender = None
def serialize(self):
return json.dumps({
'seqno': self.seqno,
'oid' : self.oid})
class Messenger(ExportedGObject):
def __init__(self, tube, initiator, view):
ExportedGObject.__init__(self, tube, PATH)
self.initiator = initiator
self._tube = tube
self._entered = False
self._slots = {}
self._view = view
self._view.connect('frame-changed', self._frame_changed_cb)
self._view.connect('ground-changed', self._ground_changed_cb)
self._view.connect('sound-changed', self._sound_changed_cb)
self._tube.watch_participants(self._participant_change_cb)
def _participant_change_cb(self, added, removed):
if not self._entered and added:
self.me = self._tube.get_unique_name()
slots = [('%s:%d' % (FRAME, i), f) \
for i, f in enumerate(Document.tape)] + \
[(GROUND, Document.ground), (SOUND, Document.sound)]
for i in slots:
self._slots[i[0]] = Slot()
if self.initiator:
self._tube.add_signal_receiver(self._ping_cb, '_ping', IFACE,
path=PATH, sender_keyword='sender')
for i in slots:
slot = self._slots[i[0]]
slot.seqno = 0
slot.oid = i[1].id
slot.sender = self.me
else:
self._pong_handle = self._tube.add_signal_receiver(
self._pong_cb, '_pong', IFACE, path=PATH,
sender_keyword='sender')
self._ping()
self._tube.add_signal_receiver(self._notify_cb, '_notify', IFACE,
path=PATH, sender_keyword='sender')
self._entered = True
# incomers' signal to retrieve initial snapshot
@signal(IFACE, signature='')
def _ping(self):
logger.debug('send ping')
pass
# object is ready to post snapshot to incomer
@signal(IFACE, signature='')
def _pong(self):
logger.debug('send pong')
pass
# slot was changed
@signal(IFACE, signature='ss')
def _notify(self, slot, raw):
pass
# the whole list of slots for incomers
@method(dbus_interface=IFACE, in_signature='', out_signature='a{ss}',
sender_keyword='sender')
def _snapshot(self, sender=None):
logger.debug('_snapshot requested from %s' % sender)
out = {}
for i, slot in self._slots.items():
out[i] = slot.serialize()
return out
# fetch content of specified object
@method(dbus_interface=IFACE, in_signature='ss', out_signature='say',
sender_keyword='sender', byte_arrays=True)
def _fetch(self, type, oid, sender=None):
logger.debug('_fetch requested from %s type=%s oid=%s' \
% (sender, type, oid))
return object_serialize(type, oid)
def _ping_cb(self, sender=None):
if sender == self.me:
return
logger.debug('_ping received from %s' % sender)
self._pong()
def _pong_cb(self, sender=None):
if sender == self.me:
return
logger.debug('_pong sent from %s' % sender)
# we've got source for _snapshot and don't need _pong anymore
self._tube.remove_signal_receiver(self._pong_handle)
self._pong_handle = None
remote = self._tube.get_object(sender, PATH)
rawlist = remote._snapshot()
logger.debug('snapshot received len=%d' % len(rawlist))
for slot, raw in rawlist.items():
self._receive(slot, raw, sender)
# we are ready to receive _snapshot requests
self._tube.add_signal_receiver(self._ping_cb, '_ping', IFACE,
path=PATH, sender_keyword='sender')
def _notify_cb(self, slot, raw, sender=None):
if sender == self.me:
return
logger.debug('_notify requested from %s' % sender)
self._receive(slot, raw, sender)
def _receive(self, slot, raw, sender):
cur = self._slots[slot]
new = Slot(sender, raw)
logger.debug('object received slot=%s seqno=%d sender=%s oid=%s from %s'
% (slot, new.seqno, new.sender, new.oid, sender))
if cur.seqno > new.seqno:
logger.debug('trying to rewrite newer value by older one')
return
elif cur.seqno == new.seqno:
# arrived value was sent at the same time as current one
if cur.sender > sender:
logger.debug('current value is higher ranked then arrived')
return
if cur.sender == self.me:
# we sent current and arrived value rewrites it
logger.debug('resend current with higher seqno')
self._send(slot, cur.oid)
return
else:
logger.debug('just discard low rank')
return
else:
logger.debug('accept higher seqno')
if new.oid and not object_find(slot, new.oid):
remote = self._tube.get_object(sender, PATH)
name, raw = remote._fetch(slot, new.oid, byte_arrays=True)
object_new(slot, new.oid, name, raw)
object_select(self._view, slot, new.oid)
self._slots[slot] = new
def _send(self, slot_num, oid):
slot = self._slots[slot_num]
slot.seqno += 1
slot.sender = self.me
slot.oid = oid
self._notify(slot_num, slot.serialize())
logger.debug('_send slot=%s oid=%s seqno=%d'
% (slot_num, oid, slot.seqno))
def _frame_changed_cb(self, sender, index, frame):
self._send('%s:%d' % (FRAME, index), frame and frame.id)
def _ground_changed_cb(self, sender, ground):
self._send(GROUND, ground.id)
def _sound_changed_cb(self, sender, sound):
self._send(SOUND, sound.id)
FRAME = 'frame'
GROUND = 'ground'
SOUND = 'sound'
OBJECTS = {
FRAME : char.THEMES[-1].frames,
GROUND : ground.THEMES,
SOUND : sound.THEMES }
def object_find(type, oid):
if type.startswith(FRAME):
for c in char.THEMES:
if not c:
continue
for i in c.frames:
if i.id == oid:
return i
else:
for i in OBJECTS[type.split(':')[0]]:
if i and i.id == oid:
return i
return None
def object_new(type, oid, name, raw):
logger.debug('add new object type=%s oid=%s' % (type, oid))
if type.startswith(FRAME):
object = char.RestoredFrame(oid, raw)
for i, frame in enumerate(OBJECTS[FRAME]):
if not frame.id:
OBJECTS[FRAME][i] = object
return
elif type.startswith(GROUND):
object = ground.RestoredGround(name, oid, raw)
elif type.startswith(SOUND):
object = sound.RestoredSound(name, oid, raw)
else:
logger.error('cannot create object of type %s' % type)
return
OBJECTS[type.split(':')[0]].append(object)
def object_serialize(type, oid):
object = object_find(type, oid)
if object:
return (object.name, object.serialize())
else:
logger.error('cannot find object to serialize type=%s oid=%s' \
% (type, oid))
return ('', '')
def object_select(view, type, oid):
if oid:
object = object_find(type, oid)
else:
object = None
try:
view.props.emittion = False
if type.startswith(FRAME):
index = int(type.split(':')[1])
view.props.frame = (index, object)
elif type.startswith(GROUND):
view.props.ground = object
elif type.startswith(SOUND):
view.props.sound = object
else:
logger.error('cannot find object to select type=%s oid=%s' % (type, oid))
finally:
view.props.emittion = True
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